Most cardiac pacing therapies rely on transvenous implantation of one or more electrode-bearing leads for delivery of cardiac stimuli or for sensing cardiac activity. Such leads are often tubular in shape, as are their corresponding electrode portions. Such leads are typically inserted in a vein and then positioned to have the electrode portion in and/or near the heart. In general, if no mechanism is available to anchor the electrode portion, the position of the electrodes may change over time and thereby impair delivery of the intended therapy. Consequently, a variety of in vivo anchoring mechanisms have been developed. These mechanisms include tines, barbs, and even baskets. While such mechanisms have certain advantages, there are corresponding disadvantages. For example, barbs may be difficult to reposition once deployed, and baskets typically have a spherical shape that conforms well to only a single venous cross-section. Therefore, a need exists for new electrode-bearing leads and/or electrode portions. In particular, a need exists for electrode-bearing leads and/or electrode portions that can conform to a vessel's changing cross-section and that can be repositioned relatively easily, if necessary.